Random Dopant Fluctuation-Induced Threshold Voltage Variation-Immune Ge FinFET With Metal–Interlayer–Semiconductor Source/Drain

Shin, Changho,Kim, Jeong-Kyu,Kim, Gwang-Sik,Lee, Hyunjae,Shin, Changhwan,Kim, Jong-Kook,Cho, Byung Jin,Yu, Hyun-Yong IEEE 2016 IEEE transactions on electron devices Vol.63 No.11

<P>The impact of process-induced random dopant fluctuation (RDF)-induced threshold voltage (Vth) variation on the performance of 7-nm n-type germanium (Ge) FinFETs with and without a metal-interlayer-semiconductor (MIS) source/drain (S/D) structure is investigated using 3-D TCAD simulations. In order to reduce the RDF-induced Vth variation, an MIS S/D structure with a heavily doped n-type zinc oxide (ZnO) interlayer is used in the S/D region of the Ge FinFET. Thus, without performance degradation, the Ge FinFET with an MIS S/D structure achieves approximately threefold reduction in the RDF-induced Vth variation (versus without an MIS S/D structure). The impact of various fin parameters (i. e., fin height and fin width) on the RDF-induced Vth variation is also investigated. It is noteworthy that variation is suppressed as the fin height (fin width) increases (decreases).</P>

COVID-19 Vaccination Alters NK Cell Dynamics and Transiently Reduces HBsAg Titers Among Patients With Chronic Hepatitis B

Shin Hyunjae,Lee Ha Seok,Noh Ji Yun,고준영,Kim So-Young,Park Jeayeon,Chung Sung Won,Hur Moon Haeng,Park Min Kyung,Lee Yun Bin,Kim Yoon Jun,Yoon Jung-Hwan,Ko Jae-Hoon,Peck Kyong Ran,Song Joon Young,Shin E 대한면역학회 2023 Immune Network Vol.23 No.5

Coronavirus disease 2019 (COVID-19) vaccination may non-specifically alter the host immune system. This study aimed to evaluate the effect of COVID-19 vaccination on hepatitis B surface Ag (HBsAg) titer and host immunity in chronic hepatitis B (CHB) patients. Consecutive 2,797 CHB patients who had serial HBsAg measurements during antiviral treatment were included in this study. Changes in the HBsAg levels after COVID-19 vaccination were analyzed. The dynamics of NK cells following COVID-19 vaccination were also examined using serial blood samples collected prospectively from 25 healthy volunteers. Vaccinated CHB patients (n=2,329) had significantly lower HBsAg levels 1–30 days post-vaccination compared to baseline (median, −21.4 IU/ml from baseline), but the levels reverted to baseline by 91–180 days (median, −3.8 IU/ml). The velocity of the HBsAg decline was transiently accelerated within 30 days after vaccination (median velocity: −0.06, −0.39, and −0.04 log10 IU/ml/year in pre-vaccination period, days 1–30, and days 31–90, respectively). In contrast, unvaccinated patients (n=468) had no change in HBsAg levels. Flow cytometric analysis showed that the frequency of NK cells expressing NKG2A, an NK inhibitory receptor, significantly decreased within 7 days after the first dose of COVID-19 vaccine (median, −13.1% from baseline; p<0.001). The decrease in the frequency of NKG2A+ NK cells was observed in the CD56dimCD16+ NK cell population regardless of type of COVID-19 vaccine. COVID-19 vaccination leads to a rapid, transient decline in HBsAg titer and a decrease in the frequency of NKG2A+ NK cells.

The dynamics of interacting folds under biaxial compressive stresses

Shin, Hyunjae,Dixit, Atray C.,Stone, Howard A.,Abkarian, Manouk,Kim, Pilnam The Royal Society of Chemistry 2016 SOFT MATTER Vol.12 No.15

<P>The gradual in-plane compression of a solid film bonded to a soft substrate can lead to surface wrinkling and even to the formation of a network of folds for sufficiently high strain. An understanding of how these folds initiate, propagate, and interact with each other is still lacking. In a previous study, we developed an experimental system to observe the wrinkle-to-fold transition of layered elastic materials under biaxial compressive stresses. Here we focus on the dynamic interaction of a pair of propagating folds under biaxial compression. We find experimentally that their behavior is mediated through their tips and depends on the separation of the tips and their angle of interception. When the angle is lower than 458, the two folds either form a unique fold by the coalescence of their tips when close enough, or bend their trajectories to intersect each other and form a lenticular region in analogy with cracks. When the angle is higher then 458, the folds simply intersect and form a T-like junction. We rationalize this behavior by conducting numerical simulations to visualize the stress field around the two tips and find that the initial geometric position of the tips primarily determines the final state of the folds.</P>

주택가격 변동률이 주택연금 가입에 미치는 영향 분석

신현재 ( Shin Hyunjae ) 주택도시보증공사 2019 주택도시금융연구 Vol.4 No.1

본 연구는 주택연금 가입에 영향을 주는 요인 중에서 외부적 요인으로 볼 수 있는 주택가격과 주택가격 변동률이 실제 어떠한 영향을 주는지를 실증 분석하고자 하였다. 이를 위해 2008년 1월부터 2018년 12월까지 주택연금 가입자 수, 주택가격 변동률, 주택가격 시계열 자료를 VECM모형으로 구축하여 분석을 실시하였다. 주택가격과 주택 연금 가입자 수 2개 변수로 구성된 Panel A 모형과 주택가격 변동률 변수를 추가한 Panel B 모형으로 구분하여 각각 분석을 진행하였다. VECM 모형에 대한 충격반응분석 결과 주택연금 가입자 수는 주택가격 표준편차 1단위의 충격에 정(+)의 영향을 받는 것으로 나타났다. 주택가격 변동률을 추가한 분석결과에서는 주택가격 변동률의 표준편차 1단위의 충격에 대해 (-)방향의 영향을 받는 것으로 나타났다. 예측오차의 분산분해 결과 주택연금 가입자 수는 자기 자신의 변동에 의해 가장 많은 영향을 받는 것으로 나타났고 주택가격과 주택가격 변동률도 일정수준 영향을 미치는 것을 확인할 수 있었다. 주택가격 변동률은 주택연금 가입자 수에 시차 1에서 시차 5까지 부(-)의 영향이 점점 증가하다가 시차 6에서부터 영향력이 줄어들면서 (-)영향을 주는 것으로 나타났다. 이를 통해 주택연금 가입자는 주택가격 변동률에 대해 약 5개월까지 민감하게 반응하며 이후에도 부(-)의 영향력이 지속된다고 볼 수 있다. 따라서 주택연금 가입을 활성화하기 위해서는 주택가격 변동률을 줄여 주택시장을 안정화시킬 필요가 있다. The purpose of this study is to analyze the effect of housing price and housing price change on Reverse Mortgage Subscribers. For this purpose, VECM model was constructed by analyzing the number of Reverse Mortgage subscribers, housing price change rate, and housing price time series data from January 2008 to December 2018. Panel A model, which consists of 2 variables of housing price and housing pension subscriber, and Panel B model, which added variable of housing price change rate. As a result of the impact analysis on the VECM model, the number of housing pension subscribers was positively affected by the impact of 1 unit of standard deviation of house price. The results of the analysis of the addition of the housing price change showed that the standard deviation of the house price fluctuation is affected by the negative direction of one unit. The housing price change rate has been shown to have a negative effect on the number of Reverse Mortgage subscribers from the time lag 1 to the lag 5, As a result, the housing pension subscriber responds sensitively to the housing price fluctuation rate for about 5 months, and it’s negative influence continued. Therefore, in order to activate Reverse Mortgage subscription, it is necessary to stabilize the housing market by reducing the housing price change rate.

법규 개정이 제도의 정착과정에 미친 영향분석 - 퇴직연금 제도를 중심으로 -

신현재 ( Hyunjae Shin ) 한국정책학회 2016 韓國政策學會報 Vol.25 No.3

제도는 국회가 제정하는 법률과 관계부처의 행정규칙을 바탕으로 운영된다. 어떤 제도가 처음 도입되고 제도가 정착되는 과정에는 일정한 시간이 필요하기 마련이고, 시행과정에서 발생되는 문제점 등을 관련법규에 반영하여 제도의 미비점을 보완하게 된다. 본 연구는 2005년 12월에 처음 도입된 퇴직연금 제도를 중심으로 지난 10년 간 제도의 변천과정을 살펴본 후, 관련 법규개정이 퇴직연금 제도의 정착과정에 미친 영향을 분석하였다. 분석결과 제도의 정착과정에서 크게 4번의 정책 개입이 있었고, 이를 정책 대상 집단의성격과 정책 행위자의 권력 작용의 형태로 구분하여 분석한 결과 제1기는 “강요(force)형”,제2기와 제4기는 “영향(influence)형”, 그리고 제3기는 “지배(domination)형” 정책 개입으로 구분할 수 있었다. 개입-ARIMA 모형을 통한 정책 개입의 효과를 분석한 결과 제1기부터 제4기 모두 전체 퇴직연금 적립금에는 유의미한 영향을 미치지 못하였지만, 제1기의 “강요(force)형”의 경우 DB형 적립금 증가에 유의미한 영향을 주었고, 제2기와 제4기의 “영향(influence)형”은 각각 IRP와 DC형 적립금 증가에 유의미한 영향을 미친 것으로 나타났다. 제3기의 “지배(domination)형”은 전체 적립금 및 각 제도별 적립금에 유의미한 영향을 미치지 못하는 것으로 나타났다. 또한 제2기와 제4기 모두 “영향(influence)형” 정책 개입으로 분류할 수 있으나, 제도 도입의 (-)요인을 제거한 제2기의 정책 개입 보다 제도 도입에 (+)요인을 추가한 제4기 정책 개입의 효과가 더 크게 나타날 수 있음을 확인할 수 있었다. The institutional process requires a certain amount of time that the institution was introduced and established. Reflecting such problems occurring in the course of implementing the relevant laws and regulations will complement the deficiencies of the institution. In this study that looked after the transition process of the institution diffusion over the last decade around the retirement pension plan was first introduced in December 2005, policy interventions that were analyzed had an impact on the retirement pension plan. There are four period of policy intervention involved in the institutional settlement process. The first period of policy intervention that was prohibited additional payment on the former system. The Financial Supervision Commission Regulation of amendments was analyzed as having a low impact. The first period policy intervention as type of "force type" had found that the biggest impact on the institutional settlement process. "domination type" of the third period policy intervention was found on a small effect on the institutional settlement process. The second period policy intervention and the fourth period, but all can be classified into “influence type” policy intervention. The policy that added tax benefits had more effect on settlement of institution than removing the negative factors the settlement of institution.

Current-Voltage Model for Negative Capacitance Field-Effect Transistors

Hyunjae Lee,Youngki Yoon,Changhwan Shin IEEE 2017 IEEE electron device letters Vol.38 No.5

<P>In this letter, a semi-analytical current-voltage model for a negative capacitance field-effect transistor (NCFET) with a ferroelectric material (i.e., BaTiO<SUB>3</SUB>) is proposed. Surface potential (ψ<SUB>S</SUB>) in the channel region is determined first by solving the Landau-Khalatnikov (LK) equation numerically with Poisson's equation. Then, the drain-current is achieved based on the current continuity equation using ψ<SUB>S</SUB> determined earlier. In addition, by introducing a fitting potential for a given drain-voltage,threshold voltage shift can be captured, resulting in accurate surface potential and drain-current at different gate voltages. We have verified our model using the technology computer-aided design (TCAD)-MATLAB simulation, and our model exhibits an excellent agreement to the simulation results. In addition, the impacts of the ferroelectric thickness and channel doping concentration on the device performance and hysteresis window of NCFET are thoroughly explored.</P>

Importance Analysis of Decision Making Factors for Selecting International Freight Transportation Mode

Hyunjae JUNG,Jaewon KIM,Kwang Sup SHIN 한국해운물류학회 2019 The Asian journal of shipping and Logistics Vol.35 No.1

Currently, the competition among carriers in the international freight service industry is getting fierce. In particular, the LCC (Low Cost Carriers) in Korea secured the licenses for international freight delivery service. However, due to the high costs, most shippers prefer car ferry services over air transportation, even though the service level of air transportation is considerably better. The present paper investigates how the LCCs, as compared to car ferry services, secure the competitive advantage in the international transportation service as compared to car ferry services. We have focused on the factors shippers regard as the most important for selecting transportation mode. For a reasonable comparison, we have limited the business area to the north eastern Asian countries, including Korea, China, Japan, and Russia. We have developed a questionnaire for the shippers who export their own product in these countries from Korea. Based on the results of fuzzy-AHP, it can be concluded that the factors related to the reliability and convenience are regarded as the important factors for selecting the transportation mode. Furthermore, the results of this study can be used by LCCs to develop their own strategies for competing with car ferry services.

Van der Waals heterostructure with direct transfer of h-BN on as grown single crystalline graphene

Hyunjae Yoo,Seug-gyun Kang,Seh-Yoon Lim,Yong-seung Shin,Jaeyoung Lim,Dongmok Whang 한국진공학회 2018 한국진공학회 학술발표회초록집 Vol.2018 No.8

Monitoring the Physicochemical Degradation of Polishing Pad Soaked in Hydrogen Peroxide during Chemical Mechanical Polishing

Shin, Cheolmin,Chung, Hyunjae,Kim, Eungchul,Hong, Seokjun,Kwak, Donggeon,Jin, Yinhua,Kulkarni, Atul,Kim, Taesung The Electrochemical Society 2018 ECS journal of solid state science and technology Vol.7 No.2

<P>The porous polyurethane polishing pads are extensively used in the chemical mechanical polishing. The pad property is very important and influences the polishing effectiveness and the wafer surface quality. Hence, in the present work, the physicochemical degradation of unused polyurethane polishing pads during metal chemical mechanical polishing (CMP) in the presence of hydrogen peroxide (H2O2) was studied. It was found that the polishing pads were reacted chemically with H2O2 resulting in degradation of the polymer chain network of polishing pad and reduction in the pad elastic modulus. Pad polymer network chain scission was observed during FT-IR evaluation confirming the degradation of the pad. CMP experiments with the H2O2 soaked pads resulted in change in material removal rate (MRR) and the within-wafer non-uniformity (WIWNU). Further Pad elastic modulus estimated by colorimetric evaluation and CIE Lab color coordinates. (C) 2018 The Electrochemical Society.</P>

Random Variation Analysis and Variation-Aware Design of Symmetric Tunnel Field-Effect Transistor

Hyunjae Lee,Seulki Park,Youngtaek Lee,Hyohyun Nam,Changhwan Shin Institute of Electrical and Electronics Engineers 2015 IEEE transactions on electron devices Vol. No.

<P>A variation-immune symmetric tunnel field-effect transistor (S-TFET) is proposed for the first time to implement bidirectional current flows (I<SUB>ON</SUB> = 3.6 μA/μm, IOFF = 23 pA/μm at VDD = 0.5 V) with the steep-switching feature of a subthreshold slope (SS) <; 60 mV/dec (SS = 47 mV/dec) and to alleviate the impact of random variation. A random variation analysis with the three major random variation sources, i.e., line-edge roughness, random dopant fluctuation, and work-function variation, is performed to quantitatively evaluate the impact of each variation source on the performance of the device. To perform variation-aware design for the S-TFET, the key device parameter (i.e., the thickness of the intrinsically doped silicon pad layer) is optimized to minimize the impact of random variation on the threshold voltage (V<SUB>T</SUB>) and SS. For ultralow power applications with a sub-0.5 V power supply voltage (V<SUB>DD</SUB>), the variation-robust S-TFET is one of several promising device structures.</P>